The listed numbers, are numbers which haven't been taken, for example Oshima Yuko the 13th. The last Yuko was the 12th of that name.

Successor names that are links to other pages are the current successors.

(Ps: Aside from Ue Kara Mariko, none of these succession songs are canon)
(Ps 2: If there is a member in AKB or it's sister groups that you'd like your character to succeed, yet she isn't here on this list, feel free to ask here or in the comments on this page if it's all right for your character to succeed that person, and I'll likely add her to the list, and then you'll simply have to wait until the name gets available.)